#!/usr/bin/perl -w
use strict;

use HTTP::Date;
use Time::HiRes;
$\ ="\n";

my %month = (Jan => 0,
Feb => 31,
Mar => 59,
Apr => 90,
May => 120,
Jun => 151,
Jul => 181,
Aug => 212,
Sep => 243,
Oct => 273,
Nov => 304,
Dec => 334);

my $httpdate = 'Wed, 25 Aug 2010 09:56:38 GMT';

sub mytime {
my $year = substr($_[0],12,4);
my $days =  ($year-1970)*365+ # days in full year passed
        sprintf('%d', ($year-1970)/4)+ # add leap days in years passed
        $month{substr($_[0],8,3)}+ # add days in full months passed
        (substr($_[0],5,2)-1)+ #is doing a -1 to day of month needed?
        (((($year)%4) == 0 && (($month{substr($_[0],8,3)}+substr($_[0],5,2)) > 59))?1:0); #have we passed the leap day in the current year?
return $days*86400+(substr($_[0],17,2)*60*60)+(substr($_[0],20,2)*60)+substr($_[0],23,2); #hrs/mins/secs
}

sub mytime2 {
my $year = substr($_[0],12,4);
my $days =  ($year-1970)*365+ # days in full year passed
        ((($year-1970) - (($year-1970) % 4))/4)+ # add leap days in years passed
        $month{substr($_[0],8,3)}+ # add days in full months passed
        (substr($_[0],5,2)-1)+ #is doing a -1 to day of month needed?
        (((($year)%4) == 0 && (($month{substr($_[0],8,3)}+substr($_[0],5,2)) > 59))?1:0); #have we passed the leap day in the current year?
return  $days*86400+(substr($_[0],17,2)*60*60)+(substr($_[0],20,2)*60)+substr($_[0],23,2); #hrs/mins/secs
}
my $t_a = Time::HiRes::time();
for (0 .. 100000) {mytime($httpdate);}
print 'with sprintf int '.(Time::HiRes::time()-$t_a)."\n";;

$t_a = Time::HiRes::time();
for (0 .. 100000) {mytime2($httpdate);}
print 'with algebra int '.(Time::HiRes::time()-$t_a)."\n";;

$t_a = Time::HiRes::time();
for (0 .. 100000) {str2time($httpdate);}
print 'with HTTP date '.(Time::HiRes::time()-$t_a)."\n";;

print "algorithm outputs";
print mytime($httpdate);
print mytime2($httpdate);
print str2time($httpdate);